Boiler shows A14, burner output limited, may not reach set temperature

Safety: This is a low-voltage circuit; still isolate power before working on wiring.

• Check sensor location: Ensure the Herz outdoor sensor is mounted on a north or northwest wall, away from direct sun or heat sources.
• Inspect cable: Look for damage where the cable enters the building and at the boiler connection terminals.
• Bypass test (for skilled users): Temporarily disconnect the sensor and fit a resistor matching a typical outdoor temperature to confirm the boiler responds correctly.
• Replace sensor: If readings are clearly wrong or A14 persists, install a new Herz outdoor sensor and reconfigure weather compensation if needed.